Geologic formations are used for many applications such as hydrocarbon production, geothermal production, and carbon dioxide sequestration. Typically, boreholes are drilled into the formations to provide access to them. Various downhole tools may be conveyed in the boreholes in order to characterize the formations. Characterization of the formations and the fluids within provides valuable information related to the intended use of the formation so that drilling and production resources can be used efficiently.
One type of downhole tool is a nuclear magnetic resonance (NMR) tool that measures the nuclear magnetic properties of formation materials. NMR logging data of unconsolidated sands suggests that solid invasion into the formation may occur. Solid invasion is the phenomenon of fine particles in the drilling mud invading into the formation before or during the forming of mud cake. This phenomenon may also occur for carbonate reservoir. Fine carbonate particles produced from the drilling, especially when a polycrystalline diamond compact (PDC) bit is used, mixes into the mud and may then invade into the formation for some or many carbonate wells with favorable porosity and permeability condition. Because solid invasion can affect NMR measurements of formation materials of interest, it would be well received in the drilling and geophysical exploration industries if the effects of solid invasion could be quantified.